In recent years, in an image forming apparatus (for example, an MFP), a sheet finishing apparatus is provided to be adjacent to the rear stage of the MFP in order to perform a finishing on a sheet after image formation. The sheet finishing apparatus is called a finisher, and is for punching a hole in the sheet fed from the MFP or for performing a stapling and for ejecting it. Besides, a sheet bundle is folded in half and is ejected.
In the sheet finishing apparatus (finisher) as stated above, when the power is turned on or if a return is made from a power saving mode to a normal mode, trial operation is performed in order to confirm whether a sheet receiving mechanism operates normally.
Besides, if a sheet is clogged in the inside of the sheet finishing apparatus and a jam occurs, it is necessary to remove the jam. At the time of the jam removal operation, since the user touches the inside of the machine, there is a case where various devices are moved to positions shifted from their home positions. Thus, after the jam removal, various mechanisms are returned to the home positions and the trial operation is performed.
If the trial operation as stated above is performed, since there is a person who works near the MFP according to the office environment, when the MFP or the finisher suddenly starts the operation, the sound is very offensive to the ear.
Especially, when some devices constituting a mechanism simultaneously operate, the sound pressure level rises and the sound is disagreeable. Besides, there is a case where the fluctuation of the sound pressure abruptly occurs, and becomes a noise which is offensive to the ear.
Besides, a sheet ejection port for ejecting a sheet bundle subjected to a stapling is provided in the inside of the finisher, and since noise generated in a space extending from a stapler to the sheet ejection port is reflected and resonates in the space, reverberant sound occurs, and the noise is discharged from the sheet ejection port to the outside.
Besides, since the finisher includes the sheet ejection port, there is a danger that the user touches an inside device through the ejection port.
Further, if the finisher is provided to be adjacent to the MFP, although the power of the finisher is supplied from the MFP, since the capacity of current supplied from the MFP to the finisher is limited, it is necessary to reduce the power consumption.
JP-A-2002-307780 discloses an image forming apparatus in which noise is reduced. In this example, sound absorbing means is provided in the inside of the image forming apparatus.
JP-A-4-332673 discloses an image forming apparatus in which noise is reduced. In this example, a speaker is provided which outputs a sound wave to cancel a noise when the noise is generated.
JP-A-2004-123239 discloses an exhaust structure of an image forming apparatus. In this example, a screen member is provided at a joint between the image forming apparatus and a finishing apparatus.
JP-A-11-180617 discloses a sheet ejection mechanism of an image forming apparatus. In this example, a safety bar is provided in order to prevent a finger from being nipped at the time of movement of a paper storage tray.
JP-A-9-73251 discloses a finishing apparatus of a sheet member. In this example, the increase of power consumption and the increase of noise caused by an initializing operation are suppressed.
JP-A-2000-278469 discloses a facsimile apparatus including a sensor control device. In this example, the power consumption of a sensor is reduced.
However, in the above examples, the reduction of noise and the reduction of power consumption are still insufficient, and there is a room for further improvement.